/**
 * @author ZCR
 * @create 2025/9/8 20:55
 */
public class LCR126 {
    public int fib(int n) {
        int mod = 1000000007;
        if(n<=1) return n;
        int f1 = 0, f2 = 1;
        for(int i=2;i<=n;i++) {
            int temp = (f1 + f2) % mod;
            f1 = f2;
            f2 = temp;
        }
        return f2;
    }

    public static void main(String[] args) {
        LCR126 lc = new LCR126();
        System.out.println(lc.fib(45));
    }
}
